/ Dictionary / Index J jack oak: Meaning and Definition of Find definitions for: jack' oak" Pronunciation: [key] the blackjack, Quercus marilandica. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. jack Mormon jack-of-all-trades Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language